title: Photoperiodic control of seasonal breeding in ewes: modulation of the negative feedback action of estradiol.
mesh_terms: D000780:Anestrus / Q000528:radiation effects; D000818:Animals; D001947:Breeding; D002369:Castration; D004958:Estradiol / Q000494:pharmacology*; D005246:Feedback; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D008027:Light; D007986:Luteinizing Hormone / Q000097:blood; D010060:Ovulation / Q000187:drug effects / Q000528:radiation effects*; D010507:Periodicity; D011247:Pregnancy; D012621:Seasons; D012756:Sheep / Q000502:physiology*
chemical_list: D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone